Is Ageing A Disease?

With mice being genetically engineered to live 26% longer than average, age-incidence of a broad spectrum of age-related disease being reduced in the lab and dietary restriction significantly increasing lifespan across species, research seeking treatment for ageing is in action. Telomere modification, free radical level reduction and human growth hormone replacement, all dawn as promising avenues, which may not only decelerate, but may one day reverse the changes associated with ageing. Whilst, current knowledge of the biology of ageing remains too incomplete to assess whether interventions, such as the above, will one day extend average and maximum lifespan, one must the core question: Is ageing even a disease?

Diseases should be cured, it is accepted that this includes age-related diseases. From cancer to neurodegenerative diseases, age is the major risk factor for the majority of these serious illnesses. Treating each individual disease, has a relatively small effect on life expectancy, compared to tackling the process of ageing itself was treated. The definition of disease is historically ambiguous and sensitive to cultural perspectives, homosexuality used to be thought of as a mental illness and late-onset Alzheimer’s disease was only defined as a pathology in 1977. Disease is regarded clinically as the state in which the limits of the normal have been transgressed, health is considered in terms of the absence of disease and expected level of function, at a given gender and age. As ageing is universal, it would seem it is natural, but this does not alter the reality that ageing is a deterioration of normal function. If chronological devices exist, all bodies that exist can be said to age relative to the measurements provided by this, in this way physicians are interested in a set of biological changes over time, such as a higher frequency of cells with chromosomal aberrations in the elderly to decreased melanin formation and white hairs (Hayflick 1974), these changes are universal and inevitable. However, universality and inevitability do not disproof ageing as a disease, rather a special type of disease which everyone inevitably endures.

As one ages, a number of pathologies are gained, to include loss of homeostasis and molecular damage accumulation, which result in the same outcome as severe disease states – death. The perspective of modern biogerontology concludes there is little to distinguish ageing from a disease state, yet there is a reluctance to view ageing itself as a disease. These unremarkable natural processes in the aged, are confidently viewed as disease where they occur in the young, for example consider the premature ageing disease, progeria. Weismann (1891) argued that ageing and debilitation must be seen as the organism’s new mutational and adaptive responses to fluctuating environments, so ageing benefits the population by removing the superannuated and allowing evolutionary change to take place, which implies ageing to be a very natural part of life. Paradoxically, the evolutionary theory of ageing (ageing being a consequence of a reduction in the force of selection against mutations with deleterious effects later in life, leads to accumulation within population alleles with deleterious effects) potentially illustrates ageing as a lethal genetic disease, with no purpose in terms of fitness. It has been put forward, that evolutionary selection rarely act on entire species or population, rather on individuals and their phenotypic traits which may confer an advantage in certain environments, increasing the likelihood of passing on genes. In this way it is more likely that ageing can be seen as a lethal genetic disease, rather than an evolutionary process under selection. So should ageing be redefined? It seems appropriate, furthermore, a clinical redefinition of ageing as a disease state may lead to added benefits, such as proper safety and efficiency testing of anti-ageing treatments.

Obvious personal, social, economic and environmental problems spring to mind when considering life extension, although a similar change occurred since ancient times (e.g. compare Ancient Assyrians Hebrews and Romans to Syrians, israelis greeks and italians today there has been an increase from 35 to 75 years) and human nature has been able to cope, granted this is no proof that it will be able to do it again given a much greater scale of change. Nevertheless, this does not hold as a compelling argument against the research; with a clever enough government, policies can be put in place when the time comes.

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About Sumaya Anwar

Sumaya Anwar is a student of biological sciences at UCL, with a special interest in genetics. Having previous experience as a broadcast journalist, producer and researcher, she now actively works as a presenter and writer. An outgoing, sociable person, she is always interested in finding out others opinions in the pursuit of seeing an issue from every angle. This is reflected in her writing, with a versatile style that would suit a multitude of different topics. Holding a strong belief that a combination of ambition and hard work make anything possible, Sumaya perseveres to make science assessable as well as understandable to everyone.